9,563 research outputs found
How we treat bleeding associated with direct oral anticoagulants
Direct oral anticoagulants are at least as effective as vitamin K antagonists for the prevention and treatment of thromboembolism. Unfortunately, differently from vitamin K antagonists, they have the great drawback of lacking specific antidotes in the case of bleeding or emergency situations such as trauma, stroke requiring thrombolysis, and urgent surgery. The progressive development of antidotes for these new drugs, which, it is hoped, will become available in the near future, will allow better and safer management of the rapid reversal of their anticoagulant effect
The management of a blood donor bitten by a snake
The worldwide burden of snakebite is high and venomous snakes are found in many regions of the world and are a threat to public health. In Italy, for instance, viper bites are an infrequent but not negligible event. Although people who have been bitten by a snake rarely wish to donate blood within a "short" time, it is however important to evaluate their eligibility to donate blood or blood components as their donation could be a problem for donor management, especially if a specific policy is not in place. The aim of this manuscript is to summarise the worldwide existing donor deferral policy for snakebites and to provide some indications in order to facilitate decision-making and to guarantee maximum safety for the donors as well as for the recipients
The random phase approximation applied to ice
Standard density functionals without van der Waals interactions yield an
unsatisfactory description of ice phases, specifically, high density phases
occurring under pressure are too unstable compared to the common low density
phase I observed at ambient conditions. Although the description is
improved by using functionals that include van der Waals interactions, the
errors in relative volumes remain sizable. Here we assess the random phase
approximation (RPA) for the correlation energy and compare our results to
experimental data as well as diffusion Monte Carlo data for ice. The RPA yields
a very balanced description for all considered phases, approaching the accuracy
of diffusion Monte Carlo in relative energies and volumes. This opens a route
towards a concise description of molecular water phases on surfaces and in
cavities
The use of fibrinogen concentrate for the management of trauma-related bleeding. A systematic review and meta-analysis
Haemorrhage following injury is associated with significant morbidity and mortality. The role of fibrinogen concentrate in trauma-induced coagulopathy has been the object of intense research in the last 10 years and has been systematically analysed in this review. A systematic search of the literature identified six retrospective studies and one prospective one, involving 1,650 trauma patients. There were no randomised trials. Meta-analysis showed that fibrinogen concentrate has no effect on overall mortality (risk ratio: 1.07, 95% confidence interval: 0.83-1.38). Although the metaanalytic pooling of the current literature evidence suggests no beneficial effect of fibrinogen concentrate in the setting of severe trauma, the quality of data retrieved was poor and the final results of ongoing randomised trials will help to further elucidate the role of fibrinogen concentrate in traumatic bleeding
Lipid-free Antigen B subunits from echinococcus granulosus: oligomerization, ligand binding, and membrane interaction properties
Background:
The hydatid disease parasite Echinococcus granulosus has a restricted lipid metabolism, and needs to harvest essential lipids from the host. Antigen B (EgAgB), an abundant lipoprotein of the larval stage (hydatid cyst), is thought to be important in lipid storage and transport. It contains a wide variety of lipid classes, from highly hydrophobic compounds to phospholipids. Its protein component belongs to the cestode-specific Hydrophobic Ligand Binding Protein family, which includes five 8-kDa isoforms encoded by a multigene family (EgAgB1-EgAgB5). How lipid and protein components are assembled into EgAgB particles remains unknown. EgAgB apolipoproteins self-associate into large oligomers, but the functional contribution of lipids to oligomerization is uncertain. Furthermore, binding of fatty acids to some EgAgB subunits has been reported, but their ability to bind other lipids and transfer them to acceptor membranes has not been studied.<p></p>
Methodology/Principal Findings:
Lipid-free EgAgB subunits obtained by reverse-phase HPLC were used to analyse their oligomerization, ligand binding and membrane interaction properties. Size exclusion chromatography and cross-linking experiments showed that EgAgB8/2 and EgAgB8/3 can self-associate, suggesting that lipids are not required for oligomerization. Furthermore, using fluorescent probes, both subunits were found to bind fatty acids, but not cholesterol analogues. Analysis of fatty acid transfer to phospholipid vesicles demonstrated that EgAgB8/2 and EgAgB8/3 are potentially capable of transferring fatty acids to membranes, and that the efficiency of transfer is dependent on the surface charge of the vesicles.<p></p>
Conclusions/Significance:
We show that EgAgB apolipoproteins can oligomerize in the absence of lipids, and can bind and transfer fatty acids to phospholipid membranes. Since imported fatty acids are essential for Echinococcus granulosus, these findings provide a mechanism whereby EgAgB could engage in lipid acquisition and/or transport between parasite tissues. These results may therefore indicate vulnerabilities open to targeting by new types of drugs for hydatidosis therapy.<p></p>
Strain-induced tuning of the electronic Coulomb interaction in 3d transition metal oxide perovskites
Epitaxial strain offers an effective route to tune the physical parameters in
transition metal oxides. So far, most studies have focused on the effects of
strain on the bandwidths and crystal field splitting, but recent experimental
and theoretical works have shown that also the effective Coulomb interaction
changes upon structural modifications. This effect is expected to be of
paramount importance in current material engineering studies based on
epitaxy-based material synthesization. Here, we perform constrained random
phase approximation calculations for prototypical oxides with a different
occupation of the d shell, LaTiO3 (d1), LaVO3 (d2), and LaCrO3 (d3), and
systematically study the evolution of the effective Coulomb interactions
(Hubbard U and Hund's J) when applying epitaxial strain. Surprisingly, we find
that the response upon strain is strongly dependent on the material. For
LaTiO3, the interaction parameters are determined by the degree of localization
of the orbitals, and grow with increasing tensile strain. In contrast, LaCrO3
shows the opposite trends: the interactions parameters shrink upon tensile
strain. This is caused by the enhanced screening due to the larger electron
filling. LaVO3 shows an intermediate behavior
Self-consistent theory of intrinsic localized modes: application to monatomic chain
A theory of intrinsic localized modes (ILMs) in anharmonic lattices is
developed, which allows one to reduce the original nonlinear problem to a
linear problem of small variations of the mode. This enables us to apply the
Lifshitz method of the perturbed phonon dynamics for the calculations of ILMs.
In order to check the theory, the ILMs in monatomic chain are considered. A
comparison of the results with the corresponding molecular dynamics
calculations shows an excellent agreement.Comment: 9 pages, 1 figure, 1 tabl
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